scholarly journals The Allele Frequency of the HFE gene mutation H63D (rs1799945) and Its Relationship to a Hereditary Hemochromatosis Diagnosis in Metabolic Nutrition Students at Virginia Tech

2020 ◽  
Vol 16 (4) ◽  
pp. 51-57
Author(s):  
Tyler Ferqueron ◽  
Angela Anderson ◽  
Deborah Good
Keyword(s):  
Allele Frequency ◽  
Mutant Allele ◽  
Iron Absorption ◽  
Population Analysis ◽  
Genetic Diseases ◽  
Hereditary Hemochromatosis ◽  
Virginia Tech ◽  
Hfe Gene ◽  
Excess Iron ◽  
Mutant Allele Frequency

Hereditary hemochromatosis (HH) is a disease that causes excess iron absorption from the diet. This excess iron can be stored in the liver, skin, heart, pancreas, and joints, and then can lead to other health conditions, as the human body has no way of actively excreting iron. The human hemochromatosis protein (HFE protein) is encoded by the HFE gene, and mutations in this gene can lead to a dysfunction of the protein resulting in HH or iron overload later in adulthood. The objective of this study was to analyze the mutant allele frequency and the penetrance of the H63D mutation (SNP rs1799945) of the HFE gene in a cohort of Virginia Tech students. This study had a total of 69 participants. Fifty-two participants provided saliva samples, genomic data from 23andMe®, and surveys with phenotypic information. Of these, 6 were genotyped using the RFLP technique and served as controls for genotype confirmation. An additional 17 participants provided saliva samples, but did not provide 23andMe® data; genomic DNA from these participants were genotyped using the RFLP technique. Our results showed that although none of the participants had been diagnosed with HH, the mutant allele frequency of this population was 13.04%. In conclusion, as HH is usually diagnosed in older adults, we could not identify any students with a phenotype of HH, even though we could detect the mutant allele. This data suggests that affordable and accessible genetic ancestry and health kits such as the 23andMe® kit, could provide an efficient way to identify, prevent, and manage HH and other genetic diseases before symptoms arise. KEYWORDS: Hereditary Hemochromatosis; Iron Absorption; Single Nucleotide Polymorphism; Restriction Fragment Length Polymorphism; College Student Population; 23andMe®; Population Analysis; Survey Results

scholarly journals Identification of a Clinical Cutoff Value for Multiplex KRASG12/G13 Mutation Detection in Colorectal Adenocarcinoma Patients Using Digital Droplet PCR, and Comparison with Sanger Sequencing and PNA Clamping Assay

2020 ◽  
Vol 9 (7) ◽  
pp. 2283
Author(s):  
Kyung Ha Lee ◽  
Tae Hee Lee ◽  
Min Kyung Choi ◽  
In Sun Kwon ◽  
Go Eun Bae ◽  
...  
Keyword(s):  
Allele Frequency ◽  
Mutant Allele ◽  
Sanger Sequencing ◽  
Colorectal Adenocarcinoma ◽  
Diagnostic Sensitivity ◽  
Absolute Quantitation ◽  
Tissue Samples ◽  
Mutant Allele Frequency ◽  
Mutational Status

KRAS (Kirsten rat sarcoma 2 viral oncogene homolog) is a major predictive marker for anti-epidermal growth factor receptor treatment, and determination of KRAS mutational status is crucial for successful management of colorectal adenocarcinoma. More standardized and accurate methods for testing KRAS mutation, which is vital for therapeutic decision-making, are required. Digital droplet polymerase chain reaction (ddPCR) is an advanced digital PCR technology developed to provide absolute quantitation of target DNA. In this study, we validated the clinical performance of ddPCR in determination of KRAS mutational status, and compared ddPCR results with those obtained by Sanger sequencing and peptide nucleic acid-clamping. Of 81 colorectal adenocarcinoma tissue samples, three repeated sets of KRASG12/G13 mutation were measured by ddPCR, yielding high consistency (ICC = 0.956). Receiver operating characteristic (ROC) curves were constructed to determine KRASG12/G13 mutational status based on mutant allele frequency generated by ddPCR. Using the best threshold cutoff (mutant allele frequency of 7.9%), ddPCR had superior diagnostic sensitivity (100%) and specificity (100%) relative to the two other techniques. Thus, ddPCR is effective for detecting the KRASG12/G13 mutation in colorectal adenocarcinoma tissue samples. By allowing definition of the optimal cutoff, ddPCR represents a potentially useful diagnostic tool that could improve diagnostic sensitivity and specificity.

scholarly journals Iron age: novel targets for iron overload

Hematology ◽  
2014 ◽  
Vol 2014 (1) ◽  
pp. 216-221 ◽  
Author(s):  
Carla Casu ◽  
Stefano Rivella
Keyword(s):  
Iron Overload ◽  
Iron Age ◽  
Iron Metabolism ◽  
Iron Absorption ◽  
Hereditary Hemochromatosis ◽  
Therapeutic Approaches ◽  
Hepcidin Expression ◽  
Beneficial Effects ◽  
Excess Iron ◽  
Major Factors

Abstract Excess iron deposition in vital organs is the main cause of morbidity and mortality in patients affected by β-thalassemia and hereditary hemochromatosis. In both disorders, inappropriately low levels of the liver hormone hepcidin are responsible for the increased iron absorption, leading to toxic iron accumulation in many organs. Several studies have shown that targeting iron absorption could be beneficial in reducing or preventing iron overload in these 2 disorders, with promising preclinical data. New approaches target Tmprss6, the main suppressor of hepcidin expression, or use minihepcidins, small peptide hepcidin agonists. Additional strategies in β-thalassemia are showing beneficial effects in ameliorating ineffective erythropoiesis and anemia. Due to the suppressive nature of the erythropoiesis on hepcidin expression, these approaches are also showing beneficial effects on iron metabolism. The goal of this review is to discuss the major factors controlling iron metabolism and erythropoiesis and to discuss potential novel therapeutic approaches to reduce or prevent iron overload in these 2 disorders and ameliorate anemia in β-thalassemia.

scholarly journals Real-Time PCR Genotyping Assay for GM2 Gangliosidosis Variant 0 in Toy Poodles and the Mutant Allele Frequency in Japan

2014 ◽  
Vol 76 (2) ◽  
pp. 295-299 ◽  
Author(s):  
Mohammad Mahbubur RAHMAN ◽  
Akira YABUKI ◽  
Moeko KOHYAMA ◽  
Sawane MITANI ◽  
Keijiro MIZUKAMI ◽  
...  
Keyword(s):  
Real Time ◽  
Allele Frequency ◽  
Real Time Pcr ◽  
Mutant Allele ◽  
Gm2 Gangliosidosis ◽  
Genotyping Assay ◽  
Mutant Allele Frequency ◽  
Pcr Genotyping

Physiologic systemic iron metabolism in mice deficient for duodenal Hfe

Blood ◽  
2007 ◽  
Vol 109 (10) ◽  
pp. 4511-4517 ◽  
Author(s):  
Maja Vujic Spasic ◽  
Judit Kiss ◽  
Thomas Herrmann ◽  
Regina Kessler ◽  
Jens Stolte ◽  
...  
Keyword(s):  
Iron Metabolism ◽  
Iron Homeostasis ◽  
Iron Absorption ◽  
Binding Capacity ◽  
Hereditary Hemochromatosis ◽  
Direct Interaction ◽  
Hfe Gene ◽  
Hepatic Iron ◽  
Primary Role ◽  
Genes Encoding

Abstract Mutations in the Hfe gene result in hereditary hemochromatosis (HH), a disorder characterized by increased duodenal iron absorption and tissue iron overload. Identification of a direct interaction between Hfe and transferrin receptor 1 in duodenal cells led to the hypothesis that the lack of functional Hfe in the duodenum affects TfR1-mediated serosal uptake of iron and misprogramming of the iron absorptive cells. Contrasting this view, Hfe deficiency causes inappropriately low expression of the hepatic iron hormone hepcidin, which causes increased duodenal iron absorption. We specifically ablated Hfe expression in mouse enterocytes using Cre/LoxP technology. Mice with efficient deletion of Hfe in crypt- and villi-enterocytes maintain physiologic iron metabolism with wild-type unsaturated iron binding capacity, hepatic iron levels, and hepcidin mRNA expression. Furthermore, the expression of genes encoding the major intestinal iron transporters is unchanged in duodenal Hfe-deficient mice. Our data demonstrate that intestinal Hfe is dispensable for the physiologic control of systemic iron homeostasis under steady state conditions. These findings exclude a primary role for duodenal Hfe in the pathogenesis of HH and support the model according to which Hfe is required for appropriate expression of the “iron hormone” hepcidin which then controls intestinal iron absorption.

Determination of the mutant allele frequency in patients with neurofibromatosis type 2 and somatic mosaicism by means of deep sequencing

2015 ◽  
Vol 54 (8) ◽  
pp. 482-488 ◽  
Author(s):  
Melanie Spyra ◽  
Benjamin Otto ◽  
Gerhard Schön ◽  
Hildegard Kehrer-Sawatzki ◽  
Victor-Felix Mautner
Keyword(s):  
Allele Frequency ◽  
Deep Sequencing ◽  
Mutant Allele ◽  
Somatic Mosaicism ◽  
Neurofibromatosis Type ◽  
Neurofibromatosis Type 2 ◽  
Mutant Allele Frequency

scholarly journals Direct comparison of quantitative digital PCR and 2-hydroxyglutarate enantiomeric ratio for IDH mutant allele frequency assessment in myeloid malignancy

Leukemia ◽  
2015 ◽  
Vol 29 (12) ◽  
pp. 2421-2423 ◽  
Author(s):  
D H Wiseman ◽  
E A Struys ◽  
D P Wilks ◽  
C I Clark ◽  
M W Dennis ◽  
...  
Keyword(s):  
Allele Frequency ◽  
Mutant Allele ◽  
Digital Pcr ◽  
Myeloid Malignancy ◽  
Enantiomeric Ratio ◽  
Mutant Allele Frequency

Duodenal nonheme iron content correlates with iron stores in mice, but the relationship is altered by Hfe gene knock-out

Blood ◽  
2003 ◽  
Vol 101 (8) ◽  
pp. 3316-3318 ◽  
Author(s):  
Robert J. Simpson ◽  
Edward S. Debnam ◽  
Abas H. Laftah ◽  
Nita Solanky ◽  
Nick Beaumont ◽  
...  
Keyword(s):  
Iron Content ◽  
Iron Absorption ◽  
Hereditary Hemochromatosis ◽  
Iron Concentration ◽  
Nonheme Iron ◽  
Hfe Gene ◽  
Liver Iron ◽  
Knock Out ◽  
Iron Stores ◽  
Knock Out Mice

Abstract Hereditary hemochromatosis is a common iron-loading disorder found in populations of European descent. It has been proposed that mutations causing loss of function of HFE gene result in reduced iron incorporation into immature duodenal crypt cells. These cells then overexpress genes for iron absorption, leading to inappropriate cellular iron balance, a persistent iron deficiency of the duodenal mucosa, and increased iron absorption. The objective was to measure duodenal iron content in Hfe knock-out mice to test whether the mutation causes a persistent decrease in enterocyte iron concentration. In both normal and Hfe knock-out mice, duodenal nonheme iron content was found to correlate with liver iron stores (P < .001, r = 0.643 and 0.551, respectively), and this effect did not depend on dietary iron levels. However, duodenal iron content was reduced in Hfe knock-out mice for any given content of liver iron stores (P < .001).

scholarly journals Differential and Limited Expression of Mutant Alleles in Multiple Myeloma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2007-2007
Author(s):  
Adam Sperling ◽  
Naim Rashid ◽  
Niccolo Bolli ◽  
David Wedge ◽  
Peter Van Loo ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Exome Sequencing ◽  
Allele Frequency ◽  
Mutant Allele ◽  
Allelic Expression ◽  
Significant Heterogeneity ◽  
Rna Seq ◽  
Mutant Allele Frequency ◽  
Large Numbers ◽  
Significant Difference

Abstract Multiple Myeloma (MM) is a heterogeneous disease but the hallmark genetic changes involve large numbers of genomic rearrangements. Recent studies have focused on attempts to identify individual driver mutations that might provide both prognostic information and unique therapeutic targets. Whole genome and exome sequencing of increasingly large numbers of patient samples have identified a number of commonly mutated genes in MM patients. However, none of these mutations are found in more than one quarter of patients and most are found in less than 10% of samples sequenced. We recently reported a large cohort of MM exome sequences involving 84 samples from 67 patients (Nat Commun. 2014;5:2997). We defined a diverse set of gene mutations with significant heterogeneity across our cohort with a median of 52 (range 21-488) mutations identified per sample. Although computational approaches can be used to prioritize mutations that are expected to alter protein structure and function, it is more challenging to determine which mutations are likely to be clinically meaningful. As a first step towards that understanding, here we report the frequency of expression of mutant alleles in Multiple Myeloma. In this study we report RNA-seq (100 million paired end reads on Illumina HiSeq) data on 14 samples from 10 MM patients for which we have previously performed exome sequencing and correlate allele-specific expression to the DNA mutant allele frequency. We find that a minority, average 27% (range 11-48%), of previously identified DNA mutations are expressed at detectable levels in MM patients. We also compared the allele frequency found in the RNA-seq to that from our exome sequencing to identify genes that demonstrate differential allelic expression and show that this is a common phenomenon in MM patients. We identified 42 such mutations in our analysis supported by at least 10 RNA-seq reads that showed a significant difference as determined by Bayesian hypothesis testing. For instance, the CCND1 mutant allele is expressed at a higher level than would be predicted based on exome-seq frequencies. Another gene showing a similar pattern of increased expression of the mutant allele in one patient was PARP4 (87% in RNA-seq vs 49% in exome-seq). Conversely, the mutant allele frequency of EIF1AX was lower than would be expected suggesting that the mutant allele may be suppressed in our patient (15% in RNA-seq vs 67% in exome-seq). Moreover, among a subset of genes previously identified as recurrently mutated within our patient samples we see that 8/11 (73%) express the mutant allele, providing further evidence that these genes may in fact be important in disease pathogenesis. Therefore, while a large number of mutations have been described in MM, only a small fraction of the mutant alleles have detectable expression and are likely to be biologically relevant. Unbalanced allelic expression of mutant alleles appears to be a relatively common occurrence in MM patients and may help explain why patients with the same identified mutation do not always behave in a similar fashion. This analysis for the first time highlights the important issue that DNA-based reporting of mutations may have significant limitations. It will be important in the future to study expression of mutant alleles in order to understand the biology, generate prognostic models and develop targeted therapies. Disclosures No relevant conflicts of interest to declare.

Alteration of mutant allele frequency in visceral metastases of melanoma.

2018 ◽  
Vol 36 (15_suppl) ◽  
pp. e21528-e21528 ◽  
Author(s):  
Viktória Doma ◽  
Orsolya Papp ◽  
Erzsébet Rásó ◽  
Tamás Barbai ◽  
Lilla Reiniger ◽  
...  
Keyword(s):  
Allele Frequency ◽  
Mutant Allele ◽  
Mutant Allele Frequency ◽  
Visceral Metastases
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